1. Field of the invention
The invention relates to a liquid crystal panel and fabrication method thereof, and more particularly, to a liquid crystal panel having improved optical properties.
2. Background
In the current display technology, liquid crystal panel having the advantages of small size, low weight, low electricity consumption, full-color display, and potentially taking the place of conventional cathode ray tube (CRT).
Generally speaking, liquid crystal panel fabrication utilizes ball spacers or photo spacers.
FIG. 1 shows a conventional liquid crystal panel using ball spacers. The panel comprises color filter substrate 101 and array substrate 102, with ball spacers 170 disposed therebetween, and liquid crystal material 180 filled therebetween to adjust the amount of light by rotation of liquid crystal when applying an electric field.
FIG. 2 shows another conventional liquid crystal panel using photo spacers. The panel comprises color filter substrate 201 and array substrate 202, with photo spacers 260 disposed therebetween, and liquid crystal material 180 filled therebetween.
FIG. 3 is a flowchart of a conventional vacuum injection process injecting liquid crystal material into a panel through an opening in a seal pattern, applying a pressure difference between the interior and exterior of the panel and capillarity.
As shown in FIG. 3, the fabrication process comprises forming a color filter substrate and an array substrate in step 30a and 30b respectively, forming an alignment layer on the two substrates respectively in step 31, rubbing the alignment layer to freely align subsequently-formed liquid crystal molecules of a liquid crystal material in step 32, forming a seal pattern with an opening in step 33, scattering ball spacers on the array substrate to maintain a uniform cell gap between the two substrates in step 34, bonding the two substrates in step 35, cutting the bonded large substrates into a plurality of small panels in step 36, injecting a liquid crystal material into each panel by vacuum injection method in step 37, sealing the opening of the panels in step 38, and cleaning the panels in step 39.
U.S. Pat. No. 20040125319 A1 discloses a liquid crystal device fabricated by conventional vacuum injection, which eliminates gravity mura.
Only a single type of spacers is normally used to maintain uniform cell gap. However, with increased panel size, possible touch mura or sound mura results if only one type of spacers is used.
Moreover, it is difficult to use vacuum injection in panel fabrications, especially in larger panel fabrications. It can take up to 5 days to inject a liquid crystal material into the cell gap of a 30-inch panel by vacuum injection, and utility rate(60% or less) of liquid crystal material is also low. There is therefore a need in panel fabrication to address the short injection time requirement and overcome problems such as touch mura and sound mura.